TNF-alpha gene polymorphism and TNF-alpha levels in obese Asian Indians with obstructive sleep apnea

Background: Obstructive sleep apnea (OSA) is emerging as a significant disorder in India. Tumor necrosis factor-α (TNFα) is an important marker of inflammation. Recent data indicate that inflammation may be an important correlate of OSA. The relationships of OSA with TNFα levels and TNFα gene promoter polymorphism (-308G/A) have not been investigated in obese Asian Indians with OSA. Objective: To look for the correlation if any, between TNFα gene promoter polymorphism (-308G/A) in obese Asian Indians with and without OSA and correlation of TNFα levels with severity of OSA. Methods and results: We studied 207 obese (BMI > 25 kg/m²) subjects; 104 with OSA and 103 without OSA. Both groups were matched for age, body mass index (BMI) and percentage body fat (%BF). Measurements included anthropometric and biochemical (fasting blood glucose, lipid profile and serum TNFα levels) parameters and TNFα gene promoter polymorphism (-308G/A). The frequency of '-308A' allele in TNFα gene was significantly higher in obese subjects with OSA (28.8%; 60/208), when compared with obese subjects without OSA (12.6%; 26/206, p = 0.001). Serum TNFα levels were significantly higher in obese subjects with OSA [(3.6 ± 0.8)pg/ml], when compared with obese subjects without OSA [(3.3 ± 0.6)pg/ml, p = 0.009]. Conclusions: Frequency of TNFα (-308A) allele and serum TNFα level was significantly higher in obese Asian Indians with OSA.